In Magnetic Resonance Imaging (“MRI”), a substance known as a contrast agent is used to enhance the contrast of structures or fluids within the patient's body. The contrast agent is MRI administered by injection into the patient's blood stream or orally, depending on the area of the body being scanned. After the contrast agent is administered, it is often desirable to determine the concentration of the contrast agent within the patient. This information can be useful on its own, or as input to determine other quantities, such as perfusion.
Conventional systems that determine the concentration of an MRI concentration agent may be broadly classified into non-invasive and invasive categories. Systems in the non-invasive category are reliant on MR image data and suffer from a lack of a baseline to compare data for independent validation. As a result, non-invasive systems are susceptible to bias and are sensitive to subtle errors and artifacts in MR images. Conversely, systems in the invasive category provide an independent validation using MR-only data, enhancing accuracy and reliability. However, these systems require the cost of risk, expense, and difficulty associated with invasive measurements. It would be desirable to have a non-invasive measure of contrast agent concentration which is independent of MR data.